Ball Screw Stroke-End Control With Integrated Nut Engagement

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Solution Overview

Problem

The conventional ball screw device requires a dedicated stopper component to regulate the stroke end of the linear motion element, leading to increased parts and potential controllability issues due to deformation and misalignment.

Innovation Solution

The ball screw device integrates a driving member with a non-rotating side engaging portion on the nut and a rotating-side engaging groove portion to regulate the stroke end of the nut, eliminating the need for a separate stopper component and improving controllability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a dedicated stopper component is used to regulate the stroke end of the linear motion element, then the stroke end regulation function is achieved, but the number of parts increases and the device becomes more complex

Engineering Contradiction:
Improvestroke end regulationVSAvoidnumber of parts
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent combines the stopper function with the driving member by providing a rotating-side engaging groove portion on the driving member that engages with the non-rotating side engaging portion on the nut. This integration eliminates the need for a separate dedicated stopper component while maintaining the stroke end regulation function, directly resolving the contradiction between reliability and device complexity

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The driving member is given multiple functions: it not only drives the screw shaft rotationally but also regulates the stroke end of the nut through the engaging groove portion. This multi-functionality reduces the total number of components needed in the system, addressing the contradiction by making one component serve multiple purposes

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Reliability

If a dedicated stopper component is used to regulate the stroke end, then the stroke end regulation function is achieved, but the axial position controllability deteriorates due to deformation and misalignment

Engineering Contradiction:
Improvestroke end regulationVSAvoidaxial position controllability
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

By integrating the stroke end regulation function into the driving member itself, the patent eliminates the interface between separate components (stopper and driving member) that could cause misalignment and deformation. The engaging groove portion and engaging portion form a unified system that maintains precise axial position controllability while achieving reliable stroke end regulation

Inventive Principle:
Principle #5Merging (Combining)

3Reliability

If a separate stopper component is used, then the stroke end regulation function is achieved, but the device size increases

Engineering Contradiction:
Improvestroke end regulationVSAvoiddevice size
Core Design Contradiction:
ReliabilityVSVolume of moving object

Solution Approach 1:

The patent merges the stopper function into the driving member structure, eliminating the need for additional space that would be required for a separate stopper component. The engaging groove portion is formed on the existing driving member, so no additional volume is needed, thereby reducing overall device size while maintaining stroke end regulation functionality

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The driving member performs both driving and stroke end regulation functions, eliminating the need for dedicated space for a separate stopper component. This multi-functionality contributes to compact device design by consolidating functions into existing components rather than adding new ones

Inventive Principle:
Principle #6Universality (Multi-functionality)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The solution allows for compact design and improved controllability by reducing the number of parts and ensuring precise axial position management of the nut, while preventing rotation deviation.

Implementation Method 1

A ball screw device is one of the machine element parts for converting linear motion to rotational motion or rotational motion to linear motion. Since balls roll between a screw shaft and a nut, a higher efficiency can be obtained compared to a sliding screw device

Methodology Applied
Scientific EffectRolling motion: Ball Bearing

Data Source

PatentEP4239217B1Ball screw device
Publication Date: 2025.08.20 NSK LTD
  • EP4239217B1 patent drawingFigure 1
  • EP4239217B1 patent drawingFigure 2
  • EP4239217B1 patent drawingFigure 3

AI summary

Provided is a ball screw device capable of regulating the stroke end of the nut, which is a linear motion element, with a small number of parts so as to make the ball screw device more compact and improve the controllability. The protruding non-rotating side engaging portion 13 is provided at the end portion on one side in the axial direction of the nut 3, and the arc-shaped rotating-side engaging groove portion 18, to which the non-rotating side engaging portion 13 can be inserted in the axial direction and can be engaged with the non-rotating side engaging portion 13 in the circumferential direction at the end portion in the circumferential direction, is provided in the driving member 5 that is fixed to the screw shaft 2 so as not to be able to rotate relative to the screw shaft 2 and rotationally drives the screw shaft 2.